> ## Documentation Index
> Fetch the complete documentation index at: https://slide.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# Skills & AGENTS.md
> Give your agents reusable instructions — on-demand or always-on
Slide supports two complementary ways to inject instructions into your agent's system prompt:
* **Skills** — progressively disclosed on-demand via the `activate_skill` tool
* **AGENTS.md** — eagerly loaded into the system prompt at init time
Both follow open standards: [Open Agent Skills](https://openagentskills.dev/docs/specification) and [AGENTS.md](https://agents.md).
**Code Examples**
Progressive skill disclosure in action
Project instructions in action
## Skills
Skills let you package reusable instructions that agents load only when they need them. Instead of stuffing everything into the system prompt, skills keep the prompt small and focused — the agent sees a short menu of available skills and activates the ones relevant to the current task.
### How skills work
1. You point the agent at one or more skill directories
2. At init time, only each skill's **name** and **description** appear in the system prompt
3. When the agent decides it needs a skill, it calls the `activate_skill` tool
4. The skill root path and full instructions from `SKILL.md` are returned to the agent as a tool result
### Creating a skill
A skill is a directory containing a `SKILL.md` file. The file has YAML frontmatter (name + description) followed by markdown instructions:
```
my-project/
└── skills/
├── code-review/
│ └── SKILL.md
└── testing/
└── SKILL.md
```
Example `SKILL.md`:
```markdown theme={null}
---
name: code-review
description: Guidelines for performing thorough code reviews
---
# Code Review Skill
## What to look for
- Correctness: Does the code do what it's supposed to?
- Readability: Is the code easy to understand?
- Performance: Are there unnecessary allocations or O(n²) loops?
- Security: Are inputs validated? Are there injection risks?
## How to format feedback
- Use inline comments for specific issues
- Summarize overall impressions at the top
- Always mention what was done well
```
#### Frontmatter requirements
| Field | Rules |
| ------------- | ------------------------------------------------------------------- |
| `name` | Lowercase alphanumeric + hyphens, max 64 chars (e.g. `code-review`) |
| `description` | Plain text, max 1024 chars |
### Using skills with an agent
```python theme={null}
from tyler import Agent
agent = Agent(
model_name="gpt-4.1",
purpose="A helpful coding assistant",
skills=[
"./skills/code-review",
"./skills/testing",
],
)
```
The agent's system prompt will include something like:
```
# Available Skills
Use the `activate_skill` tool to load full instructions for any skill.
- **code-review**: Guidelines for performing thorough code reviews
- **testing**: Guidelines for writing comprehensive tests
```
When the agent encounters a task that matches a skill, it will call `activate_skill` with the skill name and receive the full instructions.
### Using skills with config files
```yaml theme={null}
name: "MyAgent"
model_name: "gpt-4.1"
purpose: "A helpful assistant"
skills:
- "./skills/code-review"
- "./skills/testing"
- "~/shared-skills/documentation"
```
Relative paths are resolved relative to the config file's directory.
***
## AGENTS.md
AGENTS.md files provide project-level instructions that are eagerly loaded into the agent's system prompt at init time. Unlike skills (which are progressively disclosed), AGENTS.md content is always present — making it ideal for coding standards, API conventions, and other rules that should always apply.
### How it works
1. Auto-discovery is enabled by default, or you point the agent at one or more `AGENTS.md` files
2. At init time, the file contents are loaded and placed in a `` block in the system prompt
3. The agent sees these instructions on every interaction
### Creating an AGENTS.md file
Create an `AGENTS.md` file in your project root (or any directory). No special frontmatter or formatting is required — it's just markdown:
```markdown theme={null}
# Project Guidelines
## Code Style
- Use type hints for all function signatures
- Follow PEP 8 naming conventions
- Prefer `async`/`await` over threads for I/O-bound operations
## Error Handling
- Always use specific exception types (never bare `except:`)
- Include meaningful error messages with context
- Use `logging` instead of `print` for diagnostics
## API Conventions
- Use `httpx` for HTTP requests (async-native)
- Always set timeouts on external calls
- Return typed dataclasses or Pydantic models, not raw dicts
```
### Using AGENTS.md with an agent
#### Default auto-discovery
By default, Tyler discovers `AGENTS.md` files by walking upward from the current working directory:
```python theme={null}
from tyler import Agent
agent = Agent(
model_name="gpt-4.1",
purpose="A helpful coding assistant",
)
```
#### Explicit path
```python theme={null}
from tyler import Agent
agent = Agent(
model_name="gpt-4.1",
purpose="A helpful coding assistant",
agents_md="./AGENTS.md",
)
```
#### Auto-discovery
You can also set `agents_md=True` explicitly. `Agent.from_config()` starts discovery from the config file directory when `agents_md` is omitted or set to `true`:
```python theme={null}
agent = Agent(
model_name="gpt-4.1",
purpose="A helpful coding assistant",
agents_md=True,
)
```
This is useful in monorepos where you might have:
```
project-root/AGENTS.md # Company-wide rules
project-root/backend/AGENTS.md # Backend-specific rules
```
Files are loaded root-first, so the closest file's instructions appear last (taking natural precedence).
#### Disable loading
```python theme={null}
agent = Agent(
model_name="gpt-4.1",
purpose="A helpful coding assistant",
agents_md=False,
)
```
#### Multiple files
```python theme={null}
agent = Agent(
model_name="gpt-4.1",
agents_md=["./AGENTS.md", "./docs/coding-standards.md"],
)
```
Multiple files are joined with `---` separators.
### Using AGENTS.md with config files
```yaml theme={null}
name: "MyAgent"
model_name: "gpt-4.1"
purpose: "A helpful assistant"
# Default: auto-discover from this config directory upward
# agents_md: true
# Disable loading
# agents_md: false
# Explicit path
# agents_md: "./AGENTS.md"
# Multiple files
# agents_md:
# - "./AGENTS.md"
# - "./docs/coding-standards.md"
# Keep "system" unless your provider supports developer messages
instruction_role: "system"
```
Relative paths are resolved relative to the config file's directory.
### Size limits
AGENTS.md content is guarded against oversized files:
* Individual files larger than 100,000 characters are skipped with a warning
* Combined content from multiple files is truncated at 100,000 characters
If your instructions exceed this limit, consider moving task-specific content into skills instead.
***
## When to use which
| | Skills | AGENTS.md |
| ----------------- | -------------------------------------------------------- | ------------------------------------ |
| **Loading** | On-demand (progressive disclosure) | Eager (always in prompt) |
| **Best for** | Task-specific instructions the agent may or may not need | Project-wide rules that always apply |
| **Prompt impact** | Minimal — only name + description until activated | Full content always present |
| **Format** | `SKILL.md` with YAML frontmatter | Plain markdown |
Use **AGENTS.md** for short, universal project rules that should always be in context. Use **skills** for detailed, task-specific instructions that only matter sometimes. You can use both together.
## Next steps
Give your agents more capabilities
Connect to external tool servers